A Formula One racing car has to conform to regulations which fill a dense 72-page booklet. Technical illustrator Craig Scarboroughexplains next year's new rules in layman's terms, with amazingly intricate and detailed illustrations. —Ed.

Finally the FIA have published the detail of the 2011 technical regulations. There were no major surprises amongst the rules. There being rules to effectively ban: double diffusers, F-ducts & slotted rear wings. Newly introduced were the mandated weight distribution and adjustable rear wing.

There’s a lot to cover, so I won’t cover every rule change and neither can I cover them in detail. But here’s the main points (with the rule in block quotes).

Ban on connected shark fins

Another route to banning F-ducts, as well as a move to limit the ever expanding rear fin, the rule prevents any bodywork reaching the rear wing.

3.9.1 No bodywork situated between 50mm and 330mm forward of the rear wheel centre line may be more than 730mm above the reference plane.

Ban on slots in the beam wing

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With the exception of the central 15cm, the beam wing cannot have a slot that widens internals to create a blown slot. Only Williams raced this last year, but the practice has been prevented. This reinforces the fundamental rule that the lower wing should only be formed of one element.

3.10.1 Any bodywork more than 150mm behind the rear wheel centre line which is between 150mm and 730mm above the reference plane, and between 75mm and 355mm from the car centre line, must lie in an area when viewed from the side of the car that is situated between 150mm and 350mm behind the rear wheel centre line and between 300mm and 400mm above the reference plane. When viewed from the side of the car no longitudinal cross section may have more than one section in this area.

Furthermore, no part of this section in contact with the external air stream may have a local concave radius of curvature smaller than 100mm.

Once this section is defined, ‘gurney’ type trim tabs may be fitted to the trailing edge. When measured in any longitudinal cross section no dimension of any such trim tab may exceed 20mm.

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Ban on slots in the rear wing

As with the beam wing, the upper rear wing is prevented from having slots extending beyond the central 15cm. This prevent F-ducts or other blown slots, the latter which have been exploited for several years.

3.10.2 Other than the bodywork defined in Article 3.10.9, any bodywork behind a point lying 50mm forward of the rear wheel centre line which is more than 730mm above the reference plane, and less than 355mm from the car centre line, must lie in an area when viewed from the side of the car that is situated between the rear wheel centre line and a point 350mm behind it.

With the exception of minimal parts solely associated with adjustment of the section in accordance with Article 3.18:

when viewed from the side of the car, no longitudinal cross section may have more than two sections in this area, each of which must be closed.

no part of these longitudinal cross sections in contact with the external air stream may have a local concave radius of curvature smaller than 100mm.

Once the rearmost and uppermost section is defined, ‘gurney’ type trim tabs may be fitted to the trailing edge. When measured in any longitudinal cross section no dimension of any such trim tab may exceed 20mm.

The chord of the rearmost and uppermost closed section must always be smaller than the chord of the lowermost section at the same lateral station.

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Limit on rear wing support pylons

The number, thickness and cross-section of the rear wing support pylons are now more tightly controlled.

3.10.9 Any horizontal section between 600mm and 730mm above the reference plane, taken through bodywork located rearward of a point lying 50mm forward of the rear wheel centre line and less than 75mm from the car centre line, may contain no more than two closed symmetrical sections with a maximum total area of 5000mm2. The thickness of each section may not exceed 25mm when measured perpendicular to the car centre line.

Once fully defined, the section at 725mm above the reference plane may be extruded upwards to join the sections defined in Article 3.10.2. A fillet radius no greater than 10mm may be used where these sections join.

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Clarification of the starter motor hole

After some teams were exploiting oversized starter motor holes in the diffuser to create a slotted effect, the FIA clamped down with a clarification. This has now been written into the rule book.

3.12.7 No bodywork which is visible from beneath the car and which lies between the rear wheel centre line and a point 350mm rearward of it may be more than 125mm above the reference plane. With the exception of the aperture described below, any intersection of the surfaces in this area with a lateral or longitudinal vertical plane should form one continuous line which is visible from beneath the car.

An aperture for the purpose of allowing access for the device referred to in Article 5.16 is permitted in this surface. However, no such aperture may have an area greater than 3500mm2 when projected onto the surface itself and no point on the aperture may be more than 100mm from any other point on the aperture.

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Ban on Double Diffusers (DDD) and Open Exhaust Blown Diffusers (EBD)

Due to a previous weakness in the rules defining the underfloor, teams were able to exploit this to create the double diffuser. Double diffusers were only possible as an opening could be created in the gap been the reference plane, step plane and the diffuser. Now the rules close this avenue off.

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Additionally this opening allowed teams to open up the front of the diffuser to blow the exhaust through for an even greater blown diffuser effect. This rule also prevents this opening in all but the outer 50mm of the split between the diffuser and the floor.

One additional clarification is that the suspension must not form any of the measured point for the under floor. Previously the minimum height was exploited by some teams placing wishbones or Toe-Control arms across the top an opening in the diffuser.

3.12.9 In an area lying 450mm or less from the car centre line, and from 450mm forward of the rear face of the cockpit entry template to 350mm rearward of the rear wheel centre line, any intersection of any bodywork visible from beneath the car with a lateral or longitudinal vertical plane should form one continuous line which is visible from beneath the car. When assessing the compliance of bodywork surfaces in this area the aperture referred to in Article 3.12.7 need not be considered.

3.12.10 In an area lying 650mm or less from the car centre line, and from 450mm forward of the rear face of the cockpit entry template to 350mm forward of the rear wheel centre line, any intersection of any bodywork visible from beneath the car with a lateral or longitudinal vertical plane should form one continuous line which is visible from beneath the car.

3.12.11 Compliance with Article 3.12 must be demonstrated with the panels referred to in Articles 15.4.7 and 15.4.8 and all unsprung parts of the car removed.

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Driver operated F-duct

Even though the loop holes in the rear wing regulations have been closed, this additional new regulation prevents the driver influencing aerodynamics. So that other driver controlled F-duct type devices cannot be exploited other areas, such as: front wings, sidepods or diffuser.

3.15 With the exception of the parts necessary for the adjustment described in Article 3.18, any car system, device or procedure which uses, or is suspected of using, driver movement as a means of altering the aerodynamic characteristics of the car is prohibited.

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Ban on movable splitters

As with some other rules, this is a 2010 clarification now added to the regulations. Its thought that teams were allowing their splitter to flex upwards, to allow the car to run a more raked attitude and lower front wing ride height. There are now more stringent tests and restrictions on the splitter support mechanisms.

3.17.5 Bodywork may deflect no more than 5mm vertically when a 2000N load is applied vertically to it at three different points which lie on the car centre line and 100mm either side of it. Each of these loads will be applied in an upward direction at a point 380mm rearward of the front wheel centre line using a 50mm diameter ram in the two outer locations and a 70mm diameter ram on the car centre line. Stays or structures between the front of the bodywork lying on the reference plane and the survival cell may be present for this test, provided they are completely rigid and have no system or mechanism which allows non-linear deflection during any part of the test.

Furthermore, the bodywork being tested in this area may not include any component which is capable of allowing more than the permitted amount of deflection under the test load (including any linear deflection above the test load), such components could include, but are not limited to:

Joints, bearings pivots or any other form of articulation.

Dampers, hydraulics or any form of time dependent component or structure.

Buckling members or any component or design which may have, or is suspected of having, any non-linear characteristics.

Any parts which may systematically or routinely exhibit permanent deformation.

Driver adjustable rear wing

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The driver adjustable front wing is now deleted from the rules and instead the rear wing is now driver adjustable. This is because the expected benefit of greater front wing angle never provided the driver with more grip when following another car. The front flap adjustment was much more a solution to tune the cars handling in between pitstops. The TWG found that the loss of drag from the rear wing was a more effective solution to allow the following to overtake. Now the rear wing flap can pivot near its rear most point and open the slot gap from 10-15mm to up to 50mm. Opening this gap unloads the flap and reduced both downforce and drag.

This being controlled by the timing gap to the car ahead and managed by the FIA. So there’s two ways the driver can use the system. Firstly in free practice and qualifying the rear wing is solely at the control of the driver. They can adjust the wing at any point on the track and any number of times per lap. So for the ideal lap time, as soon as the car is no longer downforce dependant (straights and fast curves) the driver can operate the wing, just as they did with the F-duct. Although a small complication to the driving process, at least their hands remain on the wheel and not on a duct to the side of the cockpit.

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Then in the race the wing cannot be adjusted for two laps, then race control will send signals to the driver via the steering wheel, such that when they’re 1s or less behind another car at a designated point on the circuit, the rear wing can be trimmed out. The wing returns to the original setting as soon as the brakes are touched.

Furthermore, the distance between adjacent sections at any longitudinal plane must lie between 10mm and 15mm at their closest position, except, in accordance with Article 3.18, when this distance must lie between 10mm and 50mm.

3.18.1 The incidence of the rearmost and uppermost closed section described in Article 3.10.2 may be varied whilst the car is in motion provided:

It comprises only one component that must be symmetrically arranged about the car centre line with a minimum width of 708mm.

With the exception of minimal parts solely associated with adjustment of the section, no parts of the section in contact with the external airstream may be located any more than 355mm from of the car centre line.

With the exception of any minimal parts solely associated with adjustment of the rearmost and uppermost section, two closed sections are used in the area described in Article 3.10.2.

Any such variation of incidence maintains compliance with all of the bodywork regulations.

When viewed from the side of the car at any longitudinal vertical cross section, the physical point of rotation of the rearmost and uppermost closed section must be fixed and located no more than 20mm below the upper extremity and no more than 20mm forward of the rear extremity of the area described in Article 3.10.2 at all times.

The design is such that failure of the system will result in the uppermost closed section returning to the normal high incidence position.

Any alteration of the incidence of the uppermost closed section may only be commanded by direct driver input and controlled using the control electronics specified in Article 8.2.

3.18.2 The adjustable bodywork may be activated by the driver at any time prior to the start of the race and, for the sole purpose of improving overtaking opportunities during the race, after the driver has completed a minimum of two laps after the race start or following a safety car period.

The driver may only activate the adjustable bodywork in the race when he has been notified via the control electronics (see Article 8.2) that it is enabled. It will only be enabled if the driver is less than one second behind another at any of the pre-determined positions around each circuit. The system will be disabled by the control electronics the first time the driver uses the brakes after he has activated the system.

The FIA may, after consulting all competitors, adjust the above time proximity in order to ensure the stated purpose of the adjustable bodywork is met.

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Mandated weight distribution

Along with the supply of Pirelli control tyres they will be matched to a mandatory weight distribution. Now the cars minimum weight is 640kg, the specified minimum axle weights, equate to a weight distribution ranging between 45.5–46.7% on the front axle. This is a few percent behind the typical 2010 loadings.

4.2 Weight distribution:

For 2011 only, the weight applied on the front and rear wheels must not be less than 291kg and 342kg respectively at all times during the qualifying practice session.

If, when required for checking, a car is not already fitted with dry-weather tyres, it will be weighed on a set of dry-weather tyres selected by the FIA technical delegate.

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Double wheel tethers

For safety a doubling of the wheel tethers has been regulated. Each tether needs to pass through a different suspension member and have its own mounting points on the upright and the chassis. There’s not expected to be any performance impact with this. But the tethers are somewhat heavier, so they and the side intrusion panel are part of the reason for the greater minimum weight limit.

10.3.6 In order to help prevent a wheel becoming separated in the event of all suspension members connecting it to the car failing provision must be made to accommodate flexible tethers, each with a cross sectional area greater than 110mm2. The sole purpose of the tethers is to prevent a wheel becoming separated from the car, they should perform no other function.

The tethers and their attachments must also be designed in order to help prevent a wheel making contact with the driver’s head during an accident.

Each wheel must be fitted with two tethers each of which exceed the requirements of 3.1.1 of Test Procedure 03/07.

Each tether must have its own separate attachments at both ends which:

are able to withstand a tensile force of 70kN in any direction within a cone of 45° (included angle) measured from the load line of the relevant suspension member;

on the survival cell or gearbox are separated by at least 100mm measured between the centres of the two attachment points;

on each wheel/upright assembly are located on opposite sides of the vertical and horizontal wheel centre lines and are separated by at least 100mm measured between the centres of the two attachment points;

are able to accommodate tether end fittings with a minimum inside diameter of 15mm.

Furthermore, no suspension member may contain more than one tether.

Each tether must exceed 450mm in length and must utilise end fittings which result in a tether bend radius greater than 7.5mm.

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No more shaped wheel spokes

After the static front wheel fairings that abounded in 2009, were banned and the wheel design homologated, there must have been some surprise that Ferrari managed to create an aerodynamic wheel shape in 2010. This is partly limited now by the restriction on surface area for spokes and shaping. The limited only allows 13% of the wheel centre to be spoked, meaning that a ten spoke wheel has to have spokes just 16mm wide.

12.4.6 When viewed perpendicular to the plane formed by the outer face of the wheel and between the diameters of 120mm and 270mm the wheel may have an area of no greater than 24,000mm2.

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Clarification of mirror positions

Again when the FIA clarify a rule or make a change for safety reasons, we don’t get to see the detail of this change until its put into the regulations. The removal of outboard mirrors was brought in early last year and now the mirrors can effectively be no more than 27.5cm from the cockpit opening.

14.3.3 All parts of the rear view mirrors, including their housings and mountings, must be situated between 250mm and 500mm from the car centre line and between 550mm and 750mm from the rear edge of the cockpit entry template.

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Ban on blade roll structures

Mercedes surprised many with their blade-like roll structure, reducing the obstruction to the rear wing and allowing for a much shorter inlet tract for the engine, the solution was likely to be copied. A minimum cross section forced teams to have a wider section above the drivers head, negating the fundamental benefit of the solution.

15.2.4 The principal roll structure must have a minimum enclosed structural cross section of 10000mm2, in vertical projection, across a horizontal plane 50mm below its highest point. The area thus established must not exceed 200mm in length or width and may not be less than 10000mm2 below this point.

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Dash roll structure point maximum height

With the cockpit opening fixed at 550mm, teams have often raised the front of the chassis around the dash bulkhead to create a raised nose. In the first of several limits for both 2011 and 2013, with even more stringent plans for 2013, the height of the front of the chassis is now being controlled. The limit for this point is now 670mm, still some 120mm above the cockpit opening.

15.2.3 The highest point of the second structure may not be more than 670mm above the reference plane and must pass a static load test details of which may be found in Article 17.3.

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Limit on front chassis height

As already explained teams raise the position of the front (AA) and dash (BB) bulkheads to create space under the nose for airflow to pass in between the front wheels and reach the rear of the car. The trend for “V” sections noses, introduced on the Red Bull RB5 in 2009, makes the front of the chassis even higher, often being visible above the height of the front tyres (~660mm). Now both these bulkheads need to be at 625mm, some 75mm above the cockpit opening.

15.4.4 The maximum height of the survival cell between the lines A-A and B-B is 625mm above the reference plane.

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Limit on shaped rear impact structures

Since the 2009 aero rules, teams have been shaping the rear impact structures into ever more curved shapes to lift it clear of the diffuser and pass it underneath the beam wing. The tail of this structure must be centred at 300mm high, to prevent extreme banana shaped structures, this rule forces the structure to vary by no more 275mm.

Furthermore, when viewed from the side, the lowest and highest points of the impact absorbing structure between its rear face and 50mm aft of the rear wheel centre line may not be separated vertically by more than 275 mm.

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Craig Scarborough is a journalist/illustrator who focusses solely on the technology of F1. His technical illustrations have appeared in AtlasF1, Autosport and print magazines. He blogs about F1 technology at Scarbsf1’s Blog.